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Re: IIgs RGB to YPbPr Component experiment

mdj wrote:

Michael J. Mahon wrote:



560x384 (two display lines per Apple line) isn't too bad a match.



That'd give a pretty small image on the 15" panels it'd be
targetting... 1120x768 would probably look fairly reasonable on a 17"
or 19" digital panel...


Yes, it would!  I just gave it as a lowest common denominator
pixel mapping to square pixels.

However, making the Apple raster occupy more pixels just makes each
pixel look a little closer to a "lo-res" Apple pixel.  ;-)  Big screen
displays call for *lots* of pixels, and the Apple doesn't have them.


Unfortunately LCD's aren't quite at the resolution needed to do a nice
job. You can have either a clear picture with shonky aspect, or a
slightly distorted one that's correct aspect. It'll work well for
colour composite emulation, but not RGB or monochrome unfortunately,
without having an incorrect aspect ratio.

I'd like to see both implemented


I think we're going to see some attempts soon...



Hopefully. In the digital realm there are still ways that you can
'cheat' and get decent results. For example 80 column text doesn't
necessarily have to be implemented on a 560x192 raster to look good.
Only monochrome dhr really presents a problem, as in colour mode you're
only dealing with 140 pixels horizontally so have much more flexible
modifiers. Hires/lores/40 column is doable as 840x768, which would look
pretty reasonable I think, on most displays.


It's only "nominally" 140 pixels horizontally--it's actually 560
pixels with full artifacted glory.  ;-)  For example, the 140
Apple "pixels" don't have to be placed on mod 4 boundaries!


Actually an 840x768 raster would work pretty well for everything,
except monochrome dhr.


Not for programs that create colors across "pixel" boundaries...


I'm playing with an FPGA board myself, but have only got as far as
doubling the video rate to produce a reasonable monochrome text and
hires on VGA. More info as it happens...


Great!

-michael

Parallel computing for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."